How your windows look is important. You want to make sure they match the style and aesthetic of your home. But energy efficiency is just as crucial to consider when shopping for new windows.

Upgrading your home’s windows comes with more than a few perks, as they’re good for the environment and may help lower your heating and cooling bills, giving you a greater return on investment. And since there are a lot of factors to consider when choosing energy efficient windows, this blog will explore what you should know and what to look out for when choosing the best energy efficient windows.

Why Choosing Energy Efficient Windows Is Important

The U.S. Department of Energy estimates an annual savings of around $126-$465 by replacing single-pane windows in a house. Choosing energy efficient windows with proper installation means your home’s heating or cooling system doesn’t have to work as hard to regulate the temperature, saving you money in the long run.

By opting for green energy windows, you can also reduce your carbon footprint by as much as 3,839 compounds of CO2 a year. That’s roughly equivalent to 196 gallons of gasoline.

An inside shot of picture windows.

Which Frame Is Right for You?

Some styles of window frames are less prone to heat and cold transfer than others. Wood is often cited as superior to aluminum in this way since metals conduct temperature easier than wood. However, that doesn’t always mean wood is the best option for every household. 

We’ll explore the pros and cons of different materials below to help you choose the best energy efficient windows for your style and budget.


Vinyl is known to be one of the most cost-effective materials. Well-constructed and properly installed vinyl windows are a budget-friendly option for people focused on choosing energy efficient windows. The only major drawback to vinyl windows is that some homeowners don’t love the look of vinyl on their houses.


Wood is the best choice for people looking for maximum insulation. However, next to their vinyl and aluminum counterparts, wood often requires more upkeep and can be a bit pricier depending on fluctuating lumber prices.


Aluminum isn’t the top choice when looking for the best energy efficient windows. However, aluminum frames are durable and require little maintenance. Aluminum is prone to rust if left completely unkempt, so we recommend applying aluminum cleaner to the frames every now and then to remove excess moisture.


Wood-clad can be the best of both worlds for many homeowners. Usually consisting of a wood or vinyl exterior with a temperature transfer-resistant wood interior, this type of window is a good choice for most homeowners. However, wood-clad windows can be prone to water infiltration, especially in the sills and jambs, making them a better option for people residing in more temperate climates.

A handheld device measuring how to choose energy efficient windows.

The Best Energy Efficient Windows

The design of a window doesn’t matter as much as the materials it’s made of, but it’s important to know your options, as some may work better than others depending on your home’s layout. Below is a list of three common types of window design:

  • Double-hung windows. Especially common in pre-war buildings, double-hung windows are popular across the U.S. and are efficient choices for most homeowners.
  • Casement windows. Casement windows have a crank that swings the window open. This allows them to seal much more tightly than other types of windows.  Casement windows typically require maintenance on their hinges and seals for continued efficiency.
  • Picture windows. This type of window – especially if it’s a glass with a gas-filled interior – can be especially efficient. The only drawback is the limited shape and size options associated with this aesthetic.

Guidelines for Choosing Energy Efficient Windows

Thankfully, you don’t have to leave it up to the manufacturer or play a guessing game when choosing energy efficient windows. Since green energy windows offer the promise of environmental gains (like a reduced carbon footprint), there is a standardized system and set of guidelines used for determining the energy efficiency and efficacy of a window.

What Is an Energy Star Rating for Windows?

ENERGY STAR is a government-backed and trusted symbol of efficiency. The ENERGY STAR label was established to reduce greenhouse gas emissions and other pollutants and make it easier for consumers to identify and purchase energy efficient products.

For a window to earn the ENERGY STAR label, it must meet the following specifications:

  • Contribute to significant energy savings nationwide.
  • Deliver features and performance based on consumer demand.
  • Offer energy consumption and performance that can be verified by testing.
  • Ensure that if the product is more expensive than a less-efficient counterpart, purchasers will recover their investment through increased energy efficiency.

Low-E Coating Windows

Low-E coating windows were developed to minimize the amount of ultraviolet and infrared light that can pass through the glass pane. With an extremely thin and transparent coating, low-E windows reflect long-wave infrared energy away from the inside of a home and back outside.

This helps regulate inside temperatures and can even protect furniture and personal items (such as photographs) from experiencing fading or damage from the sun.

NFRC Window Ratings

NFRC stands for the National Fenestration Rating Council. This is a nonprofit organization established to standardize ways of testing the performance of windows and doors. When assessing NFRC window energy performance ratings, there are few factors to consider:

  1. U-Factor. In general, the U-Factor for windows ranges from 0.20 to 1.20. The lower the U-Factor, the better the window insulates.
  2. Air leakage. This measures how much airflow enters through your windows and into your home. A loosely-sealed window emitting a lot of airflow will produce a drafty home.
  3. Solar heat gain coefficient (SHGC). This measures a window’s efficiency in preventing solar heat from entering the inside of a home. A product with a low SHGC rating is more effective at reducing cooling loads during the summer by blocking heat gain from the sun.
  4. Visible transmittance. This measures how well a window allows natural light to enter a home.

What is a U-Factor Rating for Windows?

The U-Factor measures how well the window insulates. The SHGC measures how much of the sun’s heat comes through the window (it can range in value from 0 to 1). The lower the SHGC, the less solar heat the window lets in.

Get a Tax Credit for Energy Efficient Windows

Choosing energy efficient windows doesn’t just save you money by lowering your monthly energy bill – it can also help you receive a tax credit. Qualified improvements include energy efficient exterior windows, doors, and skylights. 

You may be able to earn these credits if you made energy-saving improvements to your primary home during any given taxable year.

How to Select Replacement Windows for Your Home

Choosing energy efficient windows comes down to finding a qualified manufacturer that partners with expert contractors. No matter how energy efficient the window materials are, green energy windows could actually lead to a higher monthly energy bill (instead of a lower one) if installed improperly.

To find a contractor that specializes in expert window installation, visit our contractors page or contact us with additional questions about choosing energy efficient windows.